Field of the Invention
The present invention relates to a separation preventing device that prevents separation of a fluid pipe in a pipe axis direction. More particularly, the present invention relates to a separation preventing device that has elasticity by which even when unexpected external force such as earthquake occurs in a fluid pipe network formed by connecting a plurality of fluid pipes, a connection portion of the fluid pipe expands and contracts in the pipe axis direction in response to the external force by a predetermined acceptable length, and has earthquake resistance by which the fluid pipe is prevented from being separated beyond the acceptable length.
Description of the Related Art
In a separation preventing device and a pipe joint of the related art, an engaging piece (a locking member) having a plurality of locking claws (wedge portions) is housed in a recess portion of a clamping plate (a main body member) externally fitted onto an outer peripheral surface of an original pipe (a pipe spigot), the clamping plate (the main body member) is provided with a pressing screw (a pressing member), and when the external force due to earthquake or the like is generated in a direction of separating the fluid pipe in the pipe axis direction, by pressing the locking claws (the wedge portions) against the outer peripheral surface of the fluid pipe, the locking claws (the wedge portions) are caused to bite into the fluid pipe to prevent the separation of the fluid pipe in the pipe axis direction (for example, see Utility Model Publication No. 52-166815 (page 3, FIG. 3)).
Moreover, in the separation preventing device and the pipe joint of the related art, in a recess portion of a pressing ring (a main body member) externally fitted to an outer peripheral surface of a pipe spigot, a pressing bolt (a pressing member) is provided in the pressing ring (the main body member) in which a retaining member (a locking member) having a plurality of projections (wedge portions) is housed, and when external force due to an earthquake or the like is generated in a direction of separating the pipe spigot in a pipe axis direction, by pressing the plurality of projections (the wedge portions) against the outer circumferential surface of the pipe spigot, the plurality of projections (the wedge portions) is caused to bite into the pipe spigot, thereby preventing the separation of the pipe spigot in the pipe axis direction (for example, see Japanese Patent Laid-Open No. 2005-3207 (pages 5 to 7, FIGS. 1 to 4)).
Moreover, in the separation preventing device and the pipe joint of the related art, a wedge member (a locking member) having a plurality of wedge portions is housed in a recess portion of a pressing ring (a main body member) externally fitted to an outer peripheral surface of a pipe spigot (a fluid pipe), the main body member is provided with a clamping tool (a pressing member), and when external force due to earthquake or the like is generated in a direction of separating the fluid pipe in a pipe axis direction, by pressing the locking member against the outer peripheral surface of the fluid pipe via an intermediary member (an interposition member) having a tapered surface, the wedge portion is caused to bite into the fluid pipe, thereby preventing the separation of the fluid pipe in the pipe axis direction (for example, see Utility Model Publication No. 58-31027 (page 3, FIG. 3)).
Furthermore, in the separation preventing device and the pipe joint of the related art, a retainer (a locking member) having a plurality of wedge portions is housed in a recess portion of a gland (a main body member) externally fitted onto an outer peripheral surface of a pipe spigot (a fluid pipe) via a holder (an elastic body), and a pressing bolt (a pressing member) is provided in the main body member. Thus, when the external force due to an earthquake or the like is generated in a direction of separating the fluid pipe in the pipe axis direction, by pressing the locking member against the outer peripheral surface of the fluid pipe via a contact member (an interposition member), the wedge portions are caused to bite into the fluid pipe to prevent the separation of the fluid pipe in the pipe axis direction (for example, see Japanese Utility Model Publication No. 4-1434 (Page 3, FIG. 6))
Patent Document 1: Utility Model Publication No. 52-166815 (page 3, FIG. 3)
Patent Document 2: Japanese Patent Laid-Open No. 2005-3207 (pages 5 to 7, FIGS. 1 to 4)
Patent Document 3: Utility Model Publication No. 58-31027 (page 3, FIG. 3)
Patent Document 4: Utility Model Publication No. 4-1434 (Page 3, FIG. 6)
However, in Utility Model Publication No. 52-166815 (page 3, FIG. 3), when the external force due to earthquake or the like acts in a direction of separating the original pipe, the locking piece tilts, a front locking claw (an original pipe end portion side) is pressed firmly compared to a rear locking claw (an original pipe opposite end portion side), the pressing force is concentrated on the front locking claw, there is a risk of the front locking claw too deeply biting into the original pipe, and there is a problem in that the outer peripheral surface of the original pipe and an inner surface lining may be damaged, thereby shortening the life of the original pipe.
Moreover, in Japanese Patent Laid-Open No. 2005-3207 (pages 5 to 7, FIGS. 1 to 4), since a central portion of the retaining member is restricted between the pressing ring and the pressing bolt, the pressing force from the pressing bolt is concentrated on the projection of the central portion of the retaining member. Meanwhile, since a peripheral side portion extending to a side portion of the retaining member is not held by the pressing bolt and the peripheral side portion of the retaining member becomes a state of a cantilever, the peripheral side portion is deformed, and there was a fear of insufficient pressing of the projection of the peripheral side portion against the fluid pipe. As a result, there was a problem in that force is concentrated on the projection of the central portion of the retaining member, the projection excessively bites into the pipe spigot, thereby locally damaging the lining of the pipe spigot, and meanwhile, the peripheral side portion of the retaining member is deformed, and the projection of the peripheral side cannot sufficiently bite into pipe spigot.
Moreover, in Utility Model Publication No. 58-31027 (page 3, FIG. 3), when the external force caused by the earthquake or the like is repeatedly generated in a direction of separating the fluid pipe, and on the contrary, in a direction of inserting the fluid pipe, since the intermediary member (the interposition member) disposed in the recess portion without a gap in the pipe axis direction is locally concentrated on a contact surface between the pressing member and the locking member by the repeated external force in the pipe axis direction, and collides with the contact surface several times, there is a fear of damage to collision locations of these members, and consequentially there is a problem in that the separation preventing function of the fluid pipe is significantly impaired.
Furthermore, in Japanese Utility Model Publication No. 4-1434 (Page 3, FIG. 6), since the retainer (the locking member) is housed in the recess portion in a state of being biased in a circumferential direction of the fluid pipe only at one point by the holder (the elastic body), the retainer (the locking member) in the recess portion of the initial assembling stage is liable to become unstable, and at the time of assembling the separation preventing device with respect to the pipe spigot (the fluid pipe), there is a problem in that the locking member and the interposition member may fall out of the recess portion.
Furthermore, in order to prevent the locking member and the interposition member from falling out of the recess portion, when increasing the elastic force by changing a material or a shape of the elastic body, since the elastic body still applies high elastic force to the locking member after assembling, when the external force due to an earthquake or the like is generated in a direction of separating the fluid pipe, there is a problem in that the locking member does not tilt at a predetermined angle and it is not possible to exhibit the locking force as designed.
The present invention has been made in view of such problems, and an object thereof is to provide a separation preventing device of a fluid pipe that is able to prevent the excessive biting of the wedge portion of the locking member into the fluid pipe and is able to prevent the fluid pipe, the locking member, the pressing member, and the interposition member from being locally concentrated and colliding with one another to prevent damage to these members even when the external force due to earthquake or the like and the repeated external force generated in the pipe axis direction act in a direction of separating the fluid pipe, and is able to firmly maintain the separation preventing function of the fluid pipe.
The present invention has been made in view of such problems, and an object thereof is to provide a separation preventing device of a fluid pipe in which the locking member can be stably housed without falling out of the recess portion, and the locking member after assembling can exhibit the locking force as designed.